Light-based imaging systems, such as light detection and ranging (LIDAR) systems, have been used in a variety of operations to achieve range data from target areas. In its most basic form, LIDAR utilizes a light emitter, typically a laser emitter, and a light receiver, such as a photodetector. The light emitter directs light to a target area. Upon striking objects in the target area, a portion of the light is reflected back to a light receiver which registers the reflected light. By measuring the difference in time between when the light is emitted and when reflected light is received, the distance from the system to objects in the target area may be determined. This information may be used to create a topographical image of the target area.
Typical LIDAR systems utilize either a scanning beam of light or a single flash of light. Scanning systems comprise a series of mirrors to control the position of a laser beam as it is scanned across a target area. The laser is pulsed at a high rate, and the time of return is recorded for each pulse. Flash systems emit a single flash of light, which covers an entire target area, eliminating the need for scanning mirrors and a repeatedly pulsed laser. Flash systems typically utilize a photo-detector array so that different parts of the array correspond to different locations in the target area. Because these systems only create range data, they are often connected to global positioning systems to provide location information of the target area.
LIDAR systems can provide numerous advantages in a variety of fields, for instance, surveying and topographical mapping. Aircraft or satellites may be fitted with LIDAR systems to acquire information such as terrain elevation, presence of objects such as trees, or determining the changes in shore lines.